The monastery of Panagia Kosmosoteira (Our Lady, Saviour of the World) includes a fortress wall (with towers and a gate) and a catholicon (main church) in the type of the cross-in-square church with two columns and five domes. The iconographic decoration is a magnificent specimen of high quality painting of the School of Constantinople, dated to the 12th century. Built in the wall of the SE corner is a clay ornament representing an eagle. The narthex has been demolished, unknown when. The central apse and the prothesis have undergone later repairs. Also later are the four pilasters outside.

The monastery was founded in 1152 by the sevastokrator Isaakios Komnenos, the third son of Alexios I. Isaakios composed the typikon (regulations) of the monastery, and was buried there. Two hundred years later, the catholikon was converted into the mosque of Suleyman, and five and a half centuries later was again converted into a Christian church.